I bought a pair of S4i headphones for my new iPhone 3GS about 7 months ago. They worked great. However, now none of the three buttons on the remote are working. I cannot control volume, answer calls, or play/pause/fwd/rev any audio track. I thought this might be a problem with the iphone, so I rebooted it, but the buttons on the S4i still fail. I still hear audio through the headphones; its just that the buttons no longer work. Please help!